How to solve a 4x4 Rubik's Cube: a beginner guide
The 4x4, also called Rubik's Revenge, has no fixed center pieces and many more parts than a 3x3. The usual way to learn it is reduction: turn the big cube into something that behaves like a 3x3, then solve it that way. This guide explains the three stages and what to expect.
What makes the 4x4 different
A 4x4 has about 7.4 x 10^45 possible positions, far more than the 3x3. It has 8 corners, 24 edge pieces and 24 center pieces. The centers are not fixed in place, because there is no single middle piece on a face, so the colors of the faces are decided by how the centers end up grouped.
The method that most people use is called reduction. First you group the center pieces so that each face has a block of four of the same color. Then you pair up the edge pieces into 12 pairs. After that the cube acts like a 3x3 and is solved with the ordinary outer-face turns.
Notation for the extra layers
The 4x4 has inner layers that a 3x3 does not. Rw turns the outer right layer and the inner layer next to it together, and 2R turns only the inner layer next to the right face. Capital letters turn only the outer face, as on a 3x3.
The guide on cube notation covers wide turns and inner layers. Read it first if a move such as 2R or Rw looks unfamiliar.
Parity and why it exists
On a 4x4 you can reach positions that a 3x3 cannot have, such as a single flipped edge pair or two swapped edge pairs. These are called parity cases. They show up at the end of the method, when the cube looks like a 3x3 but one or two pieces are wrong, and they are fixed with a special sequence.
When this app solves a 4x4 it may begin with a single inner-layer turn such as 2R. That is a parity fix for a situation only big cubes can have, and it is done first on purpose.
What the 4x4 solver does
The 4x4 solver works by reduction as well. It groups the centers, pairs the edges and then finishes the cube like a 3x3 with ordinary outer-face turns. It finds its short move combinations by computer search, so the centers and edges look different from the hand method of building one center block at a time.
Teach me is only offered for the 2x2 and 3x3. On a 4x4 the app does not explain each step in beginner terms. If you want to learn a hand method, learn the 3x3 first with Teach me, because the last stage of a 4x4 is a 3x3 solve.
A good order to learn in
Start with the 2x2, then the 3x3, then come back to the 4x4. The 3x3 skills are needed for the final stage, and the notation is the same. Use the 4x4 solver to see what each stage looks like on your own scramble, and watch the pattern of moves on the 3D cube.
Step by step
- Solve the centers Group the 24 center pieces so each face has one block of four stickers of the same color. Keep the finished centers together while you work on the others.
- Pair the edges Join the 24 edge pieces into 12 matching pairs, one pair for each edge of the cube, without breaking up the centers.
- Solve it like a 3x3 Treat the grouped centers and paired edges as a 3x3 and solve the cube with ordinary outer-face turns.
- Fix parity if it shows up If one edge pair is flipped or two pairs are swapped, use a special parity sequence, then finish the solve.
- Check the result on the 3D cube Paint or scan your own 4x4 into the solver and play the moves one at a time to see each stage.